The invention relates to flexible shaft couplings, and more particularly, to elastomeric couplings for transmitting torque between two shafts approximately aligned on a shaft axis, i.e., to elastomeric couplings joining a pair of axially spaced shafts.
In the past such elastomeric couplings have comprised a composite member extending arcuately about an axis generally coinciding with the shaft axis and including an elastomeric center element having integrally connected first and second axially spaced portions which extend radially and in opposite axial directions, together with first and second shoes which are respectively fixed to the center element and which extend in axially opposite directions, and first and second hubs which are respectively fixed within the shoes.
In the past, the first and second portions of the center element included semi-cylindrical inner surfaces to which the outer surfaces of the axially extending inner parts of the first and second shoes were fixed or bonded. In addition, in the past, the outer surfaces of the hubs respectively included radially outwardly extending collars or shoulders which were raised above the remainder of the outer surfaces and which respectively engaged the inner surfaces of the outer parts of the first and second shoes. Such projections are shown in U.S. application Ser. No. 09/120,948, which was filed Jul. 22, 1998, which is entitled Tearing Configuration for Flexible Element of Elastomeric Coupling, and which is incorporated herein by reference. Such projections had a circular cross-section in a plane extending perpendicularly to a radial line, and had a width of about one-quarter of the axial hub length and were located closer to the outer hub ends than to the inner hub ends. Such projections also received the bolts connecting the hubs to the shoes. As a consequence, only a small portion of the hubs engaged the inner surfaces of the shoes.
Thus, these previous constructions required a stepped hub or non-uniform cylindrical hub and the urethane extended below the surface of the non-formed or streight metal shoe.
Attention is directed to U.S. Pat. No. 4,634,400, which issued Jan. 6, 1987 and which is also incorporated herein by reference.